arm: mvebu: Add support for coherency fabric in mach-mvebu

The Armada 370 and Armada XP SOCs have a coherency fabric unit which
is responsible for ensuring hardware coherency between all CPUs and
between CPUs and I/O masters. This patch provides the basic support
needed for SMP.

Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>

6 files changed, 162 insertions, 1 deletions

diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
index 94b4b9e03571..b0d075b50f29 100644
--- a/arch/arm/boot/dts/armada-370-xp.dtsi
+++ b/arch/arm/boot/dts/armada-370-xp.dtsi
@@ -36,6 +36,11 @@
               interrupt-controller;
         };
 
+        coherency-fabric@d0020200 {
+                compatible = "marvell,coherency-fabric";
+                reg = <0xd0020200 0xb0>;
+        };
+
         soc {
                 #address-cells = <1>;
                 #size-cells = <1>;
diff --git a/arch/arm/mach-mvebu/Makefile b/arch/arm/mach-mvebu/Makefile
index 57f996b6aa0e..5ce4b42c2697 100644
--- a/arch/arm/mach-mvebu/Makefile
+++ b/arch/arm/mach-mvebu/Makefile
@@ -2,4 +2,4 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
         -I$(srctree)/arch/arm/plat-orion/include
 
 obj-y += system-controller.o
-obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o irq-armada-370-xp.o addr-map.o
+obj-$(CONFIG_MACH_ARMADA_370_XP) += armada-370-xp.o irq-armada-370-xp.o addr-map.o coherency.o coherency_ll.o
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
new file mode 100644
index 000000000000..596ee66a9cc4
--- /dev/null
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -0,0 +1,82 @@
+/*
+ * Coherency fabric (Aurora) support for Armada 370 and XP platforms.
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Yehuda Yitschak <yehuday@marvell.com>
+ * Gregory Clement <gregory.clement@free-electrons.com>
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * The Armada 370 and Armada XP SOCs have a coherency fabric which is
+ * responsible for ensuring hardware coherency between all CPUs and between
+ * CPUs and I/O masters. This file initializes the coherency fabric and
+ * supplies basic routines for configuring and controlling hardware coherency
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/smp.h>
+#include <asm/smp_plat.h>
+#include "armada-370-xp.h"
+
+/*
+ * Some functions in this file are called very early during SMP
+ * initialization. At that time the device tree framework is not yet
+ * ready, and it is not possible to get the register address to
+ * ioremap it. That's why the pointer below is given with an initial
+ * value matching its virtual mapping
+ */
+static void __iomem *coherency_base = ARMADA_370_XP_REGS_VIRT_BASE + 0x20200;
+
+/* Coherency fabric registers */
+#define COHERENCY_FABRIC_CFG_OFFSET                0x4
+
+static struct of_device_id of_coherency_table[] = {
+        {.compatible = "marvell,coherency-fabric"},
+        { /* end of list */ },
+};
+
+#ifdef CONFIG_SMP
+int coherency_get_cpu_count(void)
+{
+        int reg, cnt;
+
+        reg = readl(coherency_base + COHERENCY_FABRIC_CFG_OFFSET);
+        cnt = (reg & 0xF) + 1;
+
+        return cnt;
+}
+#endif
+
+/* Function defined in coherency_ll.S */
+int ll_set_cpu_coherent(void __iomem *base_addr, unsigned int hw_cpu_id);
+
+int set_cpu_coherent(unsigned int hw_cpu_id, int smp_group_id)
+{
+        if (!coherency_base) {
+                pr_warn("Can't make CPU %d cache coherent.\n", hw_cpu_id);
+                pr_warn("Coherency fabric is not initialized\n");
+                return 1;
+        }
+
+        return ll_set_cpu_coherent(coherency_base, hw_cpu_id);
+}
+
+int __init coherency_init(void)
+{
+        struct device_node *np;
+
+        np = of_find_matching_node(NULL, of_coherency_table);
+        if (np) {
+                pr_info("Initializing Coherency fabric\n");
+                coherency_base = of_iomap(np, 0);
+        }
+
+        return 0;
+}
diff --git a/arch/arm/mach-mvebu/coherency.h b/arch/arm/mach-mvebu/coherency.h
new file mode 100644
index 000000000000..2f428137f6fe
--- /dev/null
+++ b/arch/arm/mach-mvebu/coherency.h
@@ -0,0 +1,24 @@
+/*
+ * arch/arm/mach-mvebu/include/mach/coherency.h
+ *
+ *
+ * Coherency fabric (Aurora) support for Armada 370 and XP platforms.
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __MACH_370_XP_COHERENCY_H
+#define __MACH_370_XP_COHERENCY_H
+
+#ifdef CONFIG_SMP
+int coherency_get_cpu_count(void);
+#endif
+
+int set_cpu_coherent(int cpu_id, int smp_group_id);
+int coherency_init(void);
+
+#endif  /* __MACH_370_XP_COHERENCY_H */
diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S
new file mode 100644
index 000000000000..53e8391192cd
--- /dev/null
+++ b/arch/arm/mach-mvebu/coherency_ll.S
@@ -0,0 +1,49 @@
+/*
+ * Coherency fabric: low level functions
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Gregory CLEMENT <gregory.clement@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This file implements the assembly function to add a CPU to the
+ * coherency fabric. This function is called by each of the secondary
+ * CPUs during their early boot in an SMP kernel, this why this
+ * function have to callable from assembly. It can also be called by a
+ * primary CPU from C code during its boot.
+ */
+
+#include <linux/linkage.h>
+#define ARMADA_XP_CFB_CTL_REG_OFFSET 0x0
+#define ARMADA_XP_CFB_CFG_REG_OFFSET 0x4
+
+        .text
+/*
+ * r0: Coherency fabric base register address
+ * r1: HW CPU id
+ */
+ENTRY(ll_set_cpu_coherent)
+        /* Create bit by cpu index */
+        mov     r3, #(1 << 24)
+        lsl     r1, r3, r1
+
+        /* Add CPU to SMP group - Atomic */
+        add     r3, r0, #ARMADA_XP_CFB_CTL_REG_OFFSET
+        ldr     r2, [r3]
+        orr     r2, r2, r1
+        str     r2, [r3]
+
+        /* Enable coherency on CPU - Atomic */
+        add     r3, r0, #ARMADA_XP_CFB_CFG_REG_OFFSET
+        ldr     r2, [r3]
+        orr     r2, r2, r1
+        str     r2, [r3]
+
+        dsb
+
+        mov     r0, #0
+        mov     pc, lr
+ENDPROC(ll_set_cpu_coherent)
diff --git a/arch/arm/mach-mvebu/common.h b/arch/arm/mach-mvebu/common.h
index 02f89eaa25fe..ba6b62a42f52 100644
--- a/arch/arm/mach-mvebu/common.h
+++ b/arch/arm/mach-mvebu/common.h
@@ -20,4 +20,5 @@ void mvebu_restart(char mode, const char *cmd);
 void armada_370_xp_init_irq(void);
 void armada_370_xp_handle_irq(struct pt_regs *regs);
 
+int armada_370_xp_coherency_init(void);
 #endif